We are currently updating our website, and will have our new version online soon. Please check back later this fall.

Mailing List

Subscribe to the KT Canada mailing list

Login

Welcome

Signup

Once you have signed up, you will receive a confirmation email with your username and password. To activate your account, follow the instructions in the email.

 

Centre for Evidence-
Based Medicine

Example NNTs - Opthalmology

Condition or Disorder Intervention vs. Control Outcome Follow-up Duration Event Rates % NNT (95% CI)
CER EER
Second-eye cataract surgery1 Surgery vs. control Difficulty reading normal print 6 months 35 6 4 (3 to 6)
Eyesight prevented most activities 11 0 10 (6 to 23)
Below-average overall vision 18 0 6 (4 to 10)
Eyesight interfered greatly in life 26 1 5 (3 to 7)
Stereoacuity worse than 3000-sec arc 70 12 2 (2 to 3)

References

  1. Lancet 1998 Sep 19;352(9132):925-9